A numerical analysis of the stress distribution in backfilled stopes considering nonplanar interfaces between the backfill and rock walls. Issue 3 (26th May 2016)

• Record Type: Journal Article
• Authors: Liu, Guangsheng; Li, Li; Yang, Xiaocong; Guo, Lijie
• Is Part Of: International journal of geotechnical engineering. Volume 10:Issue 3(2016)
• Page Start: 271
• Page End: 282
• Publication Date: 2016-05-26
• Subjects: Mine backfill -- Fill–wall contacts -- Nonplanar interfaces -- Stress distribution -- Numerical modeling; Geotechnical engineering -- Periodicals; Soil mechanics -- Periodicals; Rock mechanics -- Periodicals; 624.1513
• DOI: 10.1080/19386362.2015.1132123
• Languages: English
• ISSNs: 1938-6362

Abstract

Abstract : Estimation of stresses in backfilled stopes is a critical issue for backfill design in underground mines. This task can be accomplished by numerical modeling. To date, most numerical modelings were performed without considering interface elements between the backfill and rock walls. The few published works using planar fill–wall interfaces showed that the stress states can be different than those obtained by numerical modeling without considering interface elements, especially when the shear strength of the planar interfaces is lower than that of the backfill. This tends to indicate that the stress estimation in backfilled stopes must be made by accounting for the (planar) fill–wall interfaces. In practice, blasting is commonly used in hard rock mines, and the stope walls are seldom regular and planar. Consequently, it is expected to be more appropriate to analyze the mechanical behavior of the backfill by considering nonplanar interfaces. In this paper, the stress distributions along the vertical central line of 2D backfilled stopes are analyzed using FLAC3D by considering nonplanar interface elements. The asperities of nonplanar interfaces are idealized by saw teeth and the roughness of interfaces is characterized by the teeth height and angle. The numerical results show that the stress state within backfilled stopes can be largely dependent on the shear strength and geometry of the interfaces. This indicates that a survey of the actual rock wall faces should be made and taken into account in the numerical modelings to obtain a better estimate of the stresses in the backfilled stopes. Nevertheless, the results further show that the numerical modelings using planar fill–wall contacts without interface elements lead to comparable stress distributions as those obtained by considering nonplanar interface elements when the interfaces are rough enough. More results are presented by considering different stope geometries and mechanical properties of the backfill with nonplanar interface elements.